1. Field of the Invention
The present invention relates, in general, to a tape circuit substrate and a semiconductor apparatus employing the same, in which electromagnetic interference (EMI) may be substantially reduced or eliminated and where a more stable power supply voltage may be supplied.
2. Description of the Related Art
With the recent trend toward miniaturization, slimness and lightness in electronic apparatuses such as personal digital assistants (PDAs) and thin film transistor liquid crystal displays (TFT LCDs), such miniaturization, slimness and lightness are also required for the mounting of semiconductor devices installed on such electronic apparatuses.
To meet these requirements, a tape automated bonding (TAB) type of tape circuit substrate is used in mounting of semiconductor devices. According to the TAB method, bump electrodes formed in advance on a semiconductor device are collectively bonded to wiring patterns formed on a tape circuit substrate. The TAB method for forming tape circuit substrates includes chip-on-film (COF) and tape carrier package (TCP) methods.
A semiconductor apparatus in which mounting is performed by means of the TAB method is disclosed in Korean Patent Laid-Open Publication No. 2003-0005022 (the ‘022 publication’, published on Jan. 15, 2003). The '022 publication discloses semiconductor devices mounted on a circuit substrate, wherein position mismatch between the semiconductor devices and wiring patterns of the circuit substrate may be prevented.
However, for the semiconductor apparatus disclosed in the '022 publication, a plurality of ground electrodes are arranged so as to be spaced apart from one another with respect to the wiring pattern. The ground electrodes are then electrically connected to a common ground. Thus, a substantial length of the wiring is needed between each of the ground electrodes, or between the ground electrodes and the common ground. Since the length of wiring illustrated in the '022 publication is substantially long, a parasitic capacitance C, parasitic inductance L and parasitic resistance R on the wiring may be increased, and thus a transient state voltage is applied to the ground electrodes. This may be undesirable.
For example, at a time when a ground voltage is switched on, the voltage of the ground electrodes cannot reach a constant voltage (as a reference voltage) due to the parasitic capacitance, inductance and resistance. Accordingly, ripples are produced and power noise may be induced.
Recently, semiconductor devices mounted on semiconductor apparatuses such as described above have been using high-speed clock signals or logic signals to efficiently perform a variety of functions. Therefore, electromagnetic interference (EMI) may be produced (caused by electromagnetic waves irradiated directly from or propagated through these semiconductor devices). This produced EMI may disturb semiconductor devices mounted on neighboring semiconductor apparatuses, for example.
With the increased use of semiconductor apparatuses and the development of digital technologies, EMI generated from these apparatuses causes malfunction in semiconductor apparatuses performing precise functions. EMI may also have adverse influences on the human body, and adds to radio wave noise interference, which is emerging as a substantial problem.
Therefore, the minimization of EMI is currently being viewed as a necessary and important standard. Accordingly, a standard for restricting such EMI below a given value has been established, in an effort to internationally regulate EMI in such semiconductor apparatuses.